Use the Labels area in the Display Option dialog box to add or remove labels that are specific to Advanced Peak Determination (APD) data—such as the species ID, the monoisotopic mass, and the top peak in the cluster.
NOTE
The APD labels are available only if the injection or raw data file is acquired using APD during data acquisition.
The APD algorithm improves the determination of the charge states and of the monoisotopic m/z values of isotopic envelopes.
The following table describes the label options for the APD data.
Options | Description |
|---|---|
Monoisotopic mass | The monoisotopic mass of a species is the mass obtained using the exact mass of the most abundant isotope of each constituent element. |
Top peak | A centroid is labeled as the top peak of an isotope distribution by the APD algorithm if it triggered a new, charge-state detection based on the surrounding peak pattern. |
Average mass | The average mass is the average of the neutral masses of the top peaks of the charge envelope members. The average mass is available instead of the monoisotopic mass if the species is not isotopically resolved. |
When the APD algorithm identifies the mass as an average mass, the application does the following:
- Labels the mass spectral peaks with average mass in the active spectrum view.
- Labels the mass spectral peaks with the label AvgM in the following format: AvgM=123.05.
NOTE
For the mass spectral peaks with no identified average mass, no label is applied.